Windows NT family started with NT 3.1 in 1993. Modern Windows operating system versions are based on the newer Windows NT kernel that was originally intended for OS/2. Windows runs on IA-32, x86-64, and Itanium processors. Earlier versions also ran on the Alpha, MIPS, FairchildClipper, and PowerPC architectures. Some work was done to port it to the SPARC architecture. The NT kernel borrows many techniques from VMS. With NT4.0 in 1996 the shell changed from Program Manager to Explorer. CPU support included PowerPC, MIPS, and DEC Alpha for earlier versions of NT, but focuses on Itanium, 386, 486, and x64 today.